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Archive - Nov 26, 2013

Potential Treatment Target Identified for Cryptosporidium parvum

In the developing world, Cryptosporidium parvum has long been the scourge of freshwater. A decade ago, it announced its presence in the United States, infecting over 400,000 people – the largest waterborne-disease outbreak in the county's history. Its rapid ability to spread, combined with an incredible resilience to water decontamination techniques, such as chlorination, led the National Institutes of Health (NIH) in the United Sates to add C. parvum to its list of public bioterrorism agents. Currently, there are no reliable treatments for cryptosporidiosis, the disease caused by C. parvum, but that may be about to change with the identification of a target molecule by investigators at the Research Institute of the McGill University Health Centre (RI-MUHC). The findings of this study were published online on September 23, 2013 in the Antimicrobial Agents and Chemotherapy (AAC) journal. "In the young, the elderly, and immunocompromised people such as people infected with HIV/AIDS, C. parvum is a very dangerous pathogen. Cryptosporidiosis is potentially life-threatening and can result in diarrhea, malnutrition, dehydration, and weight loss," says first author of the study, Dr. Momar Ndao, Director of the National Reference Centre of Parasitology (NRCP) at the MUHC and an Assistant Professor of the Departments of Medicine, Immunology, and Parasitology (Division of Infectious Diseases) at McGill University. The oocysts of C. parvum, which are shed during the infectious stage, are protected by a thick wall that allows them to survive for long periods outside the body as they spread to a new host. C. parvum is a microscopic parasite that lives in the intestinal tract of humans and many other mammals.

Oxytocin Appears to Promote Monogamy in Humans

How is the bond between people in love maintained? Scientists at the Bonn University Medical Center have discovered a biological mechanism that could explain the attraction between loving couples: if oxytocin is administered to men and if they are shown pictures of their partner, the bonding hormone stimulates the reward center in the brain, increasing the attractiveness of the partner, and strengthening monogamy. The results were published online on November 25, 2013 in PNAS. Monogamy is not very widespread among mammals; human beings represent an exception. Comparatively many couples of the species Homo sapiens have no other partners in a love relationship. For a long time, science has therefore been trying to discover the unknown forces that cause loving couples to be faithful. "An important role in partner bonding is played by the hormone oxytocin, which is secreted in the brain," says Professor Dr. René Hurlemann, Executive Senior Physician at the Inpatient and Outpatient Department of Psychiatry and Psychotherapy of the Bonn University Medical Center. A team of scientists at the University of Bonn under the direction of Professor Hurlemann and with participation by researchers at the Ruhr University of Bochum and the University of Chengdu (China) examined the effect of the "bonding hormone" more precisely. The researchers showed pictures of their female partners to a total of 40 heterosexual men who were in a permanent relationship – and pictures of other women for comparison. First a dose of oxytocin was administered to the subjects in a nasal spray; and then a placebo at a later date. Furthermore, the scientists also studied the brain activity of the subjects with the help of functional magnetic resonance tomography.

Battle Against Honey Bee Parasite in Mexico

Mexico is one of the top five bee-producing countries worldwide and the second in exportation. However, the beekeepers can see their production being affected by the attack of a parasite, the Varroa acari, a type of mite, which feeds on hemolymph of the bees. Currently, the control methods employed are of synthetic origin, but face the main problem of generating resistance in the acari, which reduces the control’s effectiveness; in addition, is not rare to find traces of it in the bee wax and honey. A press release issued November 25, 2013, said that research by the National Institute of Forest, Agricultural, and Livestock Research (INIFAP), indicated that not treating the colonies infested by Varroa acari can lead to a 65 per cent loss in production in comparison to colonies where the acari is controlled. Seeing this disparity, researchers from the INIFAP talked to the beekeepers about organic control of the pest employing powdered thymol, which is easy to employ and cheaper. In addition, the acari doesn’t develop resistance to it nor does it generate residue on honey or bee wax if generated properly. Dr. Miguel Arechavaleta Velasco, head of research at the INIFAP, explains that Varroa is an acari that feeds on bee hemolymph; like a tick, it produces a disease in the colony called varroasis that can kill entire hives, being the main problem that beekeepers face worldwide. “Among the organic products that we have studied, thymol has given encouraging results; it’s an essential oil obtain from thyme. There are commercial thymol-based products for Varroa control, but we developed a different application form, resulting in easier and cheaper (administration by) the beekeeper.” The proposed method consists in using powdered thymol mixed with powdered sugar.

Brain Reward Gene Influences Food Choices in First Year of Life

Research has suggested that a particular gene in the brain's reward system contributes to overeating and obesity in adults. This same variant (the seven-repeat allele of the dopamine receptor 4 gene—DRD4) has now been linked to childhood obesity and tasty food choices, particularly for girls, according to a new study by Dr. Patricia Silveira and Professor Michael Meaney of McGill University and Dr. Robert Levitan of the University of Toronto. Contrary to "blaming" obese individuals for making poor food choices, Dr. Meaney and his team suggest that obesity lies at the interface of three factors: genetic predispositions, environmental stress, and emotional well-being. These findings, published in the February 2014 issue of the journal, Appetite, shed light on why some children may be predisposed to obesity, and could mark a critical step towards prevention and treatment. "In broad terms, we are finding that obesity is a product of genetics, early development, and circumstance", says Dr. Meaney, who is also Associate Director of the Douglas Mental Health University Institute Research Centre. The work is part of the MAVAN (Maternal Adversity Vulnerability & Neurodevelopment) project, headed by Dr. Meaney and Dr. Hélène Gaudreau, Project Coordinator. Their team studied pregnant women, some of whom suffered from depression or lived in poverty, and followed their children from birth until the age of ten. For the study, researchers tested 150 four-year old MAVAN children by administering a snack test meal. The children were faced with healthy and non-healthy food choices. Mothers also completed a questionnaire to address their child's normal food consumption and preferences.